JLX001 ameliorates cerebral ischemia injury by modulating microglial polarization and compromising NLRP3 inflammasome activation via the NF-κB signaling pathway

Ischemic stroke is a devastating disease with high morbidity and mortality rates, and the proinflammatory microglia-mediated inflammatory response directly affects stroke outcome. Previous studies have reported that JLX001, a novel compound with a structure similar to that of cyclovirobuxine D (CVB-D), exerts antiapoptotic, anti-inflammatory and antioxidative effects on ischemia-induced brain injury. However, the role of JLX001 in microglial polarization and nucleotide-binding oligomerization domain (NOD)-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome regulation after ischemic stroke has not been fully investigated. In this study, we used the middle cerebral artery occlusion (MCAO) method to establish a focal cerebral ischemia model and found that JLX001 attenuated the brain infarct size and improved cerebral damage. Moreover, the expression levels of proinflammatory cytokines (interleukin [IL]-1β and tumor necrosis factor [TNF]-α) were significantly reduced while those of the anti-inflammatory cytokine IL-10 were increased in the JLX001-treated group. Immunofluorescence staining and flow cytometry revealed an increased number of anti-inflammatory phenotypic microglia and a reduced number of proinflammatory phenotypic microglia in JLX001-treated MCAO mice. Western blotting analysis showed that JLX001 inhibited the expression of NLRP3 and proteins related to the NLRP3 inflammasome axis in vivo. Furthermore, JLX001 reduced the number of NLRP3/Iba1 cells in ischemic penumbra tissues. Finally, mechanistic analysis revealed that JLX001 significantly inhibited the expression of proteins related to the NF-κB signaling pathway. Additionally, pyrrolidine dithiocarbamate (PDTC), an NF-κB inhibitor, ameliorated cerebral ischemia-reperfusion injury by suppressing microglial polarization towards the proinflammatory phenotype and NLRP3 activation in vivo, further suggesting that these protective effects of JLX001 were mediated by inhibition of the NF-κB signaling pathway. These results suggest that JLX001 is a promising therapeutic approach for ischemic stroke.